Method for the production of porous webs with a leather-like grain

ABSTRACT

A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain comprising roughening a basic fabric of shrinkable fibers, optionally stretching the fabric if necessary in at least the warp or weft direction; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120*C, until the foam penetrates at least completely through the pile; drying the impregnated fabric; heating the dried impregnated fabric at 120* to 160*C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.

United States Patent 1191 R211] et al.

[ 1 Dec. 16, 1975 Wilfried Kuper, Dusseldorf-Nord, all of Germany [73] Assignee: Henkel & Cie Gmbl'l, Dusseldorf,

Germany 22 Filed: Nov. 13, 1972 21 Appl. No.: 305,804

[30] Foreign Application Priority Data Dec. 27, 1971 Germany 2164852 [52] US. Cl. 427/171; 427/209; 427/290;

427/377; 427/381 [51] Int. Cl. B05D 1/00; B05D 3/02; BOSD 3/12;

B05D 5/00 [58] Field of Search 117/7, 11, S6, 63, 135.5, ll7/l43, 68; 427/171, 209, 290, 377, 381

[56] References Cited UNITED STATES PATENTS 1,579,264 4/1926 Welch et a1 117/7 2,770,026 ll/1956 Petersilie et al. 117/68 2894855 7/1959 Wilheim et al. ll7/l35.5 X 3,030,232 4/1962 Morgenstern 117/68 3,282.721 ll/1966 lseki 117/63 3,399,102 8/1968 Matsushita et al 117/63 3,524,792 8/1970 Dawes 1. 117/1 1 X 3,620,890 1l/1971 Kcmmler 117/68 Primary Examiner-William D. Martin Assistant ExaminerSadie L. Childs Attorney, Agent, or Firml-lammond & Littell 5 7] ABSTRACT A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain comprising roughening a basic fabric of shrinkable fibers, optionally stretching the fabric if necessary in at least the warp or weft direction; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120C, until the foam penetrates at least completely through the pile; drying the impregnated fabric; heating the dried impregnated fabric at 120 to 160C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.

16 Claims, N0 Drawings METHOD FOR THE PRODUCTION OF POROUS WEBS A LEATHER-LIKE G RAIN THE PRIoR ART It is known to produce so-called leatherette cloths for cleaning purposes by impregnating a non-woven fabric with a rubber containing foam material. These cloths are highly-porous and absorbent, but they have a substantially plane and rough fiber surface which bears no similarity inits appearance and its properties with a natural leather surface. i

It is also known to produce textile webs with a leather-like surface by coating a stretched textile material on one side with an adhesive coat and a leather powder, and then subjecting the cloth to shrinking after the adhesive coat has been fixed. These cloths are used as a substitute for shoe leather and garment leather; however they fail to have a high porosity, a high absorbency, or the appearance of a beautifully grained leathery surface.

OBJECTS OF THE INVENTION It is an object of the present invention to provide textile webs of high porosity and high absorbency plus a beautifully grained leathery surface.

It is another object of the present invention to provide a method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain comprising roughening a basic fabric of shrinkable fibers .having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to 15% in warp and weft directionson at least one side in order to raise the height of the pile above the surface of the fabric from about 0.4 to, 5 mm; optionally stretching the fabric if necessary in at least the warp or weft direction up to 7%; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120C, until the foam penetrates at least completely through the pile; drying the impregnated fabric; heating the dried impregnated fabric at 120 to 160C for a time sufficient toharden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.

These and furtherobjects of the invention will become apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION The present invention is directed to a method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain comprising roughening a basic fabric of shrinkable fibers having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to in warp and weft directions, on at least one side-in order to raise the height of the pile above the surface of the fabric from about 0.4 to 5 mm; optionally stretching the fabric if necessary in at least the warp or weft direction up to 7%; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable ata temperature above 120C, until the foam penetrates at least completely through the pile; drying the impregnated fabric; heating the dried impregnated 2 fabric at 120 to 160C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.

In carrying out the method of the invention, starting material includes textile webs or fabrics which are woven from absorbent and shrinkable fibers or threads. These fabrics are woven from fibers'for example cellulose fiber, such as cotton, staple rayon or cellulose rayon, if necessary blended with synthetic fibers, like polyamide fibers, polyester fibers, or polyacrylonitrile fibers. These fabrics can be shrunk by the action of hot water at 30 to C preferably at 30 to 60C or with steam. The shrinking effect can be further increased by stretching the fabrics before or during the impregnation in the warp direction and/or the weft direction by up to 7%. In general, a shrinking of the fabric only in the warp direction or only in the weft direction will yield a more wavy surface grain, while shrinking in both directions will yield a more irregular grain pattern. The starting fabric should have a thread density of about 10 to 20 threads per centimeter in the warp direction and in the weft direction.

Before a polymer is applied to the fabric in the form of a foam dispersion, the fabric is roughened like felt, for example, by means of a roll carding roughening machine so that the pile height is raised above the surface of the fabric from about 0.4 to 5 mm, preferably 0.4 to 2 mm. The roughening can be effectedon one side or on both sides, depending on the desired end product.

Following the roughening, the roughened fabric layer is impregnated by applying a polymeric compound hardenable at a temperature above C, such as a polymer or copolymer, in the form of an aqueous fluid foam usually a liquid foam containing air. The application is effected by means of a wiper or roll device. If the fabric is to be impregnated on both sides, this can be effected in one operation or preferably in two separate operations, impregnating first one side and after intermediate drying of the one side, then impregnating the other side. It is important for the intended purpose that the foam is worked thoroughly into the roughened layer and if necessary also intothe basic fabric, so that the fibers are saturated with and/or covered by the foam material to a substantial degree or even completely. During the impregnation the fabric can remain stress-free, or preferably the fabric can be stretched by means of known devices in the longitudinal and/or the transverse direction by up to 7%, preferably 4 to 7%. An increased shrinkage can be achieved during the following hot water or steam treatment. Stretching prior to impregnation, for example, during the roughening step is also possible and yields about the same increased shrinkage effect. After the application of the foam, the fabric is transported through the drying zone of a drying apparatus utilizing, for example, hot air or infrared radiation. The drying temperature is about 80 to 120C. After drying, the polymeric material is hardened at about 120 to C, and yields a coating which is fast to washing and cleaning.

The foams used are produced by foaming aqueous dispersions of heat hardenable polymeric compounds for example, film-forming polymers or copolymers hardenable at a temperature above 120C by injecting air, nitrogen, carbon dioxide or any other gas into the dispersion, or by working air into the dispersion by means of special stirrers or rotating brushes etc. The volumetric amount of air worked in should be about three times to .10 times the volumetric amount of the initial dispersion. In order to produce a sufficiently voluminous foam the following wetting agents and foaming agents containing higher hydrocarbon substituents with 10 to 20 carbon atoms, for example anionic surface-active compounds such as alkylbenzene sulfonates, alkyl sulfonates, fatty alcohol sulfates, fatty alcohol polyalkyleneglycolether sulfates, sulfosuccinic acid ester salts or other highly foaming ionic or nonionic tensides are added to the dispersions before foaming. The foam stability necessary for the mechanical processing operation may be achieved by the addition of foam stabilizers, for example methyl cellulose or other water-soluble cellulose derivatives, or fatty acid alkanol amides of 8 to 20 carbon atoms such as coconut fatty acid-diethanol amide of 12 to 18 carbon atoms.

The selection of the heat hardenable polymeric compound depends on the film-forming capacity, plasticity, elasticity, waterproofness, etc. Particularly suitable are polymers based on acrylic acid, acrylic acid esters, acrylic acid amides, acrylonitrile, vinyl chloride, butadiene, styrene etc. as well as their copolymers, particularly butadiene-styrene, butadiene-acrylonitrile, vinyl chloride-acrylonitrile, acrylic acid ester-vinyl chloride or acrylic acid-acrylic acid ester copolymers. These polymers or copolymers are commercially available in the form of aqueous dispersions, and already contain the catalysts or other additives required for the heat hardening thereof.

Other parameters to be considered in performing the method according to the invention may include the characteristics of the foam utilized such as the structure, fluidity and penetration power of the foam. These properties depend in turn on the viscosity of the dispersions of the polymer or copolymer to be foamed. It has been found that the viscosity of this starting dispersion usually should not exceed 1000 cp and should preferably be between 100 and 350 cp. measured with the Epprecht viscosimeter. It is therefore usually necessary to dilute the commercial polymers or copolymers with an adequate amount of water before foaming. In general good foams are obtained by starting from aqueous dispersions which contain, with reference to the active ingredients, from 10 to 40% by weight, preferably 15 to 35% by weight, of one of the above mentioned polymeric compounds, from 1 to 10% by weight, preferably 2 to 5% by weight, of wetting agent or foaming agent and from 0.05 to 15% by weight, preferably 0.1 to by weight, of foam stabilizer in an aqueous dispersion. Dyes and fillers can also be incorporated into the dispersions if desired. Particularly suitable as dyes are pigment dyes, which spread easily in water and aqueous media.

The impregnation step and the heat hardening step are followed by a shrinking step which can be achieved in a simple manner by dipping the cloth into a warm or hot waterbath at 30 to 100C or by treatment with steam. A shrinkage of about 3% to is desired either in only one direction or in both the warp and the weft directio ns, so that a wavy or irregular grain pattern is formed. The cloth is now finished and can be packaged if desired and sold.

The advantages of the webs according to the invention include a high porosity and excellent high absorbency, so that they are particularly suitable for household use as cleaning cloths for various purposes. They III are used with particular advantage as dish cloths. floor cloths, dust cloths. and glass or ceramic cleaning cloths such as window cleaning cloths. etc., since they also show good stability and abrasion resistance when wet. In addition they are also suitable for cleaning and polishing shoes, etc.. .for use as linings for shoes and covers for luggage and upholstery; and because of their beautiful leather-like grain, they are useful for decorating purposes, for example as wall coverings. Particularly in the wet state the cloths are characterized by a chamoislike soft and supple feel. These cloths meet todays sanitary requirements since they can be washed in hot water and can also be dry-cleaned. The thickness of the dry cloths after the manufacture thereof is about 0.8 to 2.5 mm.

The following examples are merely illustrative of the present invention without being deemed limitative in any manner thereof.

7 EXAMPLE 1 A cotton fabric with the following characteristics:

thread density per cm in warp and weft l 1 threads directions shrinkage in warp direction 6% shrinkage in weft direction 14% weight per square meter 150 g was roughened on both sides with a roll carding roughening machine so that the pile height on both sides was raised 1.5 mm each above the surface of the fabric.

Subsequently the fabric was impregnated on both sides with a wiper apparatus with a fluid air-rich foam of a synthetic resin dispersion, containing 4 parts by volume of air per 1 part by volume of the starting dispersion with a viscosity of 200 cp (Epprecht viscosimeter). The polymeric dispersion had the following composition:

94 parts by weight butadiene-acrylonitrile mixed polymerizate (45% dispersion) 6 parts by weight alkyl benzene sulfonate of 12 carbon atoms in the alkyl chain (50% solution) 1 part by weight methyl cellulose 1.2 parts by weight dye 97.8 parts by weight softened water After the impregnation the fabric was transported through the drying zone of a hot air drying device such that the fabric was dried within 3 minutes at C and subsequently fixed for 3 minutes at C. For the formation of the leather-like surface grain structure, the fabric was transported through a waterbath at 30 to 50C and subsequently dried in known manner. The above indicated shrinkage was obtained with the formation of an irregular grain structure on both sides of the fabric.

The end product had a polymer coating of about 1 15 g/m and was particularly suitable as an imitation leather for cleaning glass surfaces such as windows, or ceramic surfaces. The impregnation product was resistant to washing with boiling water so that repeated cleaning and sanitizing of the cloth and its reuse were possible.

EXAMPLE 2 A fabric having the same characteristics as the fabric in Example 1 was roughened on one side and then was coated with a fluid air-rich foam of a polymer dispersion whic h contained 5 parts by volume of air per 1 part by volume of dispersion. The starting dispersion had the following composition: I I

- 141.0 parts by weight acrylic acid ester-vinyl chloride mixed polymerizate (45% dispersion) 30.5 parts by weight coconut fatty acid-diethanol amide having from 12 to 18 carbon atoms in the fatty acid moiety v i 11.5 parts by weight alkyl benzene sulfonate of 12 carbon atoms in the alkyl chain 50% solution) 1.2 parts by weight dye a v t 1 15.9 parts by weight softened water The viscosity was 160 cp (Epprecht viscosimeter).

After impregnating one side, the fabric was given an intermediate drying for 3 minutes. at 120C, after which the coating was similarly applied to the other side of the fabric. Subsequently the fabric was dried at 150C and the copolymer dispersion was simultaneously heat hardened onboth sides. In order to create the leatherlike surface grain on the fabric, it was treated with warm water analogously to the procedure in Example 1.

The impregnated cloth was particularly suitable as a dish cloth and dust cloth for household purposes.

EXAMPLE 3 A cotton fabric with the following characteristics:

thread density per cm in warp and weft 7 l8 threads directions I shrinkage in warp direction 3% shrinkage in weft direction 6% weight per square meter 148 g was roughened on both sides with a roll carding roughening machine so that the pile height on both sides was raised about 0.6 mm to 1 mm each above the surface of the fabric. The fabric was stretched with a suitable device by 4% in warp direction and coated in this state on both sides analogously to Example 2 by means of a wiper apparatus with an aqueous, fluid-air-rich foam of a heat hardenable filmforrning polymer. The foam contained 4 parts by volume of air per 1 part by volume of the starting dispersion. The viscosity of the starting dispersion was 280 cp (Epprecht viscosimeter). The starting dispersion had the following composition:

88.2 parts by weight acrylic acid-methyl acrylate mixed polymerizate dispersion (40%) 82.2 parts by weight polymethyl acrylate dispersion 30.0 parts by weight fatty alcohol polyethyleneglycolether sulfate-sodium salt of 12 to 14 carbon atoms in the alcohol chain (30%) 1.8 parts by weight carboxymethyl cellulose 45.0 parts by weight chalk 1.2 parts by weight dye 51.6 parts by weight softened water After drying the fabric and hardening the copolymers at 150C analogously to the procedure in Example 2, the impregnated cloth was treated in a reeling vat for 30 minutes with water of 60C for the formation of the leather-like surface grain structure.

After spinning off the excess water, the fabric was dried in the tumbler. The end product had a coating of 200 g/m of film-forming polymers and could be used advantageously as a chamois cloth for wiping dry an automobile after washing.

tion-proofness.

EXAMPLE 4 The coatingcomposition of Example 3 was applied to one side only of the fabric. The resulting article served as ashoe lining and was characterized by high breathing activity, absorbency, water-proofness and perspira- Although the present invention has been disclosed in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the new invention. All of these variations and modifications are considered to be within the true spirit and scope of the present invention as disclosed in the foregoing description and .defined by the appended claims.

We claim: I

l. A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain consisting essentially of the steps of roughening a basic fabric of shrinkable fibers having a thread density of 10 to 20 threads per centimeter in warp and weft directions and. having a shrinking capacity of 2 to 15% in warp and weft directions, on at least one side in orderto raise the height of the pile above the surface of the fabric from about 0.4 to 5 mm; optionally stretching the fabric in warp or weft direction up to 7%; in-

pregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above C, until the foam penetrates at least completely through the pile with said fluid foam being worked into the basic fabric until the fibers are saturated with and covered by said fluid foam to a substantial degree; drying the impregnated fabric; heating the dried impregnated fabric at 120 to C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.

2. Themethod according to claim 1, in which the basic fabric is woven from cellulose fibers or cellulose synthetic fiber blends.

3. The method according to claim 1, in which the height of the pile is from 0.4 to 2 mm.

4. The method according to claim 1, in which the fabric is stretched, at least during. the impregnation step, from 4 to 7% in at least the warp or weft direction.

5. The method according to claim 1, in which the aqueous fluid foam dispersion contains prior to foaming from 10 to 40% by weight of a polymeric compound selected from the group consisting of acrylic acid homopolymers, acrylic acid ester homopolymers, acrylic acid amide polymers, butadiene-acrylonitrile copolymers, acrylic acid ester-vinyl chloride copolymers and acrylic acid-acrylic acid ester copolymers.

6. The method according to claim 5, in which the aqueous fluid foam dispersion further contains, prior to foaming, from 1 to 10% by weight of a wetting agent or a foaming agent, and from 0.05 to 15% by weight of a foam stabilizer.

7. The method according to claim 6, in whichthe aqueous fluid dispersion, prior to foaming, contains (a) from 15 to 35% by weight of said polymeric compound, (b) from 2 to 5% by weight of said agent, and (c) from 0.1 to 10%by weight of said foam stabilizer.

8. The method according to claim 7, in which said wetting agent is an anionic surface-active wetting agent 7 selected from the group consisting of an alkyl benzene sulfonate, an alkyl sulfonate, a fatty alcohol sulfate. a fatty alcohol polyethylene-glycolether sulfate and a sulfosuccinic acid ester salt containing higher hydrocarbon substituent with to 20 carbon atoms in the ester group.

9. The method according to claim 7, in which said foam stabilizer c) is selected from the group consisting of methyl cellulose, carboxymethyl cellulose, and a higher fatty acid lower alkanol amide of 12 to 18 carbon atoms in the fatty acid moiety.

10. The method according to claim 1, in which said aqueous dispersion has a viscosity of not more than 1000 cp before foaming 11. The method according to claim 10, in which said aqueous dispersion has a viscosity in the range of 100 cp to 250 cp and is foamed with air or any other gas in a volumetric ratio of 1:3 to 1:10.

12. The method according to claim 1, in which said impregnated fabric is treated with hot water at 30 to 60C in order to shrink said fabric.

13. The method according to claim 1, in which both sides of the basic fabric are impregnated with said aqueous fluid foam.

14. The method according to claim 1, in which the said fluid foam is worked into the basic fabric until the fibers are completely saturated with and covered by said fluid foam.

15. A method for the production of textilewebs having high porosity and absorbency, with a leather-like surface grain consisting essentially of the steps of roughening a basic fabric of shrinkable cellulose fibers or cellulose synthetic fiber blends having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to in warp and weft directions, on at least one side in order to raise the height of the pile above the surface of the fabric from 0.4 to 5 mm; optionally stretching the fabric in the warp or weft direction up to 7%; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120C, until the foam penetrates at least completely through the pile with said fluid foam being worked into the basic fabric until the fibers are saturated with and covered by said fluid foam to a substantial degree; said aqueous fluid foam dispersion containing, prior to foaming, (a) from 10 to 40% by weight of a polymeric compound selected from the group consisting of acrylic acid homopolymers, acrylic acid ester homopolymers, acrylic acid amide polymers. butadiene-acrylonitrile copolymers. acrylic acid ester-vinyl chloride copolymers and acrylic acid-acrylic acid ester copolymers, (b) from 1 to 10% by weight of a wetting agent or a foaming agent, and (c) from 0.05 to 15% by weight of a foam stabilizer selected from the group consisting of methyl cellulose, carboxymethyl cellulose, and a higher fatty acid lower alkanol amide of 12 to 18 carbon atoms in the fatty acid moiety, said aqueous dispersion having a viscosity of not more than 1000 cp, prior to foaming, and being foamed with air or any other gas in a volumetric ratio of 1:3 to 1:10; drying the impregnated fabric; heating the dried impregnated fabric at to C for a time sufficient to harden said polymeric compound, shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain. v

16. A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain consisting essentially of the steps of roughening'a basic fabric of shrinkable fibers having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to 15% in warp and weft directions, on at least one side in order to raise the height of the pile above the surface of the fabric from about 0.4 to 5 mm; optionally stretching the fabric in the warp or weft direction up to 7%; impregnating one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120C, until the foam penetrates at least completely through the pile with "said fluid foam being worked into the basic fabric until the fibers are saturated with and covered by said fluid foam to a substantial degree; intermediately drying the fabric; impregnating the fabric on the other side thereof with said aqueous fluid foam; again drying the impregnated fabric; heating the dried impregnated fabn'c at 120 to 160C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain. 

1. A METHOD FOR THE PRODUCTION OF TEXTILE WEBS HAVING HIGH POROSITY AND ABSORBENCY, WITH A LEATHER-LIKE SURFACE GRAIN CONSISTING ESSENTIALLY OF THE STEPS OF ROUGHENING A BASIC FABRIC OF SHRINKABLE FIBERS HAVING A THREAD DENSITY OF 10 TO 20 THREADS PER CENTIMETER IN WARP AND WEFT DIRECTIONS AND HAVING A SHRINKING CAPACITY OF 2 TO 15% IN WRAP AND WEFT DIRECTIONS, ON AT LEAST ONE SIDE IN ORDER TO RAISE THE HEIGHT OF THE PILE ABOVE THE SURFACE OF THE FABRIC FROM ABOUT 0.4 TO 5MM, OPTIONALLY STRETCHING THE FABRIC IN WRAP OR WEFT DIRECTION UP TO 7%, INPREGNATING AT LEAST ONE SIDE OF THE FABRIC WITH AN AQUEOUS FLUID FOAM CONTAINING A DISPERSED OF A POLYMERIC COMPOUND HARDENABLE AT A TEMPERATURE ABOVE 120*C, UNTIL THE FOAM PENETRATES AT LEAST COMPLETELY THROUGH THE PILE WITH SAID FLUID FOAM BEING WORKED INTO BASIC FABRIC UNTIL THE FIBERS ARE SATURATED WITH AND COVERED BY SAID FLUID FOAM TO A SUBSTANTIAL DEGREE, DRYING THE IMPREGNATED FABRIC, HEATING THE DRIED IMPREGNATED FABRIC AT 120* TO 160*C FOR A TIME SUFFICIENT TO HARDEN SAID POLYMERIC COMPOUND. SHRINKING THE DRIED IMPREGNATED FABRIC BY TREAMENT WITH HOT WATER OR STEAM, AND RECOVWITH A LEATHER-LIKE SURFACE GRAIN.
 2. The method according to claim 1, in which the basic fabric is woven from cellulose fibers or cellulose synthetic fiber blends.
 3. The method according to claim 1, in which the height of the pile is from 0.4 to 2 mm.
 4. The method according to claim 1, in which the fabric is stretched, at least during the impregnation step, from 4 to 7% in at least the warp or weft direction.
 5. The method according to claim 1, in which the aqueous fluid foam dispersion contains prior to foaming from 10 to 40% by weight of a polymeric compound selected from the group consisting of acrylic acid homopolymers, acrylic acid ester homopolymers, acrylic acid amide polymers, butadiene-acrylonitrile copolymers, acrylic acid ester-vinyl chloride copolymers and acrylic acid-acrylic acid ester copolymers.
 6. The method according to claim 5, in which the aqueous fluid foam dispersion further contains, prior to foaming, from 1 to 10% by weight of a wetting agent or a foaming agent, and from 0.05 to 15% by weight of a foam stabilizer.
 7. The method according to claim 6, in which the aqueous fluid dispersion, prior to foaming, contains (a) from 15 to 35% by weight of said polymeric compound, (b) from 2 to 5% by weight of said agent, and (c) from 0.1 to 10% by weight of said foam stabilizer.
 8. The method according to claim 7, in which said wetting agent is an anionic surface-active wetting agent selected from the group consisting of an alkyl benzene sulfonate, an alkyl sulfonate, a fatty alcohol sulfate, a fatty alcohol polyethylene-glycolether sulfate and a sulfosuccinic acid ester salt containing higher hydrocarbon substituent with 10 to 20 carbon atoms in the ester group.
 9. The method according to claim 7, in which said foam stabilizer (c) is selected from the group consisting of methyl cellulose, carboxymethyl cellulose, and a higher fatty acid lower alkanol amide of 12 to 18 carbon atoms in the fatty acid moiety.
 10. The method according to claim 1, in which said aqueous dispersion has a viscosity of not more than 1000 cp before foaming.
 11. The method according to claim 10, in which said aqueous dispersion has a viscosity in the range of 100 cp to 250 cp and is foamed with air or any other gas in a volumetric ratio of 1:3 to 1:10.
 12. The method according to claim 1, in which said impregnated fabric is treated with hot water at 30* to 60*C in order to shrink said fabric.
 13. The method according to claim 1, in which both sides of the basic fabric are impregnated with said aqueous fluid foam.
 14. The method according to claim 1, in which the said fluid foam is worked into the basic fabric until the fibers are completely saturated with and covered by said fluid foam.
 15. A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain consisting essentially of the steps of roughEning a basic fabric of shrinkable cellulose fibers or cellulose synthetic fiber blends having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to 15% in warp and weft directions, on at least one side in order to raise the height of the pile above the surface of the fabric from 0.4 to 5 mm; optionally stretching the fabric in the warp or weft direction up to 7%; impregnating at least one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120*C, until the foam penetrates at least completely through the pile with said fluid foam being worked into the basic fabric until the fibers are saturated with and covered by said fluid foam to a substantial degree; said aqueous fluid foam dispersion containing, prior to foaming, (a) from 10 to 40% by weight of a polymeric compound selected from the group consisting of acrylic acid homopolymers, acrylic acid ester homopolymers, acrylic acid amide polymers, butadiene-acrylonitrile copolymers, acrylic acid ester-vinyl chloride copolymers and acrylic acid-acrylic acid ester copolymers, (b) from 1 to 10% by weight of a wetting agent or a foaming agent, and (c) from 0.05 to 15% by weight of a foam stabilizer selected from the group consisting of methyl cellulose, carboxymethyl cellulose, and a higher fatty acid lower alkanol amide of 12 to 18 carbon atoms in the fatty acid moiety, said aqueous dispersion having a viscosity of not more than 1000 cp, prior to foaming, and being foamed with air or any other gas in a volumetric ratio of 1:3 to 1:10; drying the impregnated fabric; heating the dried impregnated fabric at 120* to 160*C for a time sufficient to harden said polymeric compound, shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain.
 16. A method for the production of textile webs having high porosity and absorbency, with a leather-like surface grain consisting essentially of the steps of roughening a basic fabric of shrinkable fibers having a thread density of 10 to 20 threads per centimeter in warp and weft directions and having a shrinking capacity of 2 to 15% in warp and weft directions, on at least one side in order to raise the height of the pile above the surface of the fabric from about 0.4 to 5 mm; optionally stretching the fabric in the warp or weft direction up to 7%; impregnating one side of the fabric with an aqueous fluid foam containing a dispersion of a polymeric compound hardenable at a temperature above 120*C, until the foam penetrates at least completely through the pile with said fluid foam being worked into the basic fabric until the fibers are saturated with and covered by said fluid foam to a substantial degree; intermediately drying the fabric; impregnating the fabric on the other side thereof with said aqueous fluid foam; again drying the impregnated fabric; heating the dried impregnated fabric at 120* to 160*C for a time sufficient to harden said polymeric compound; shrinking the dried impregnated fabric by treatment with hot water or steam; and recovering said textile webs having a high porosity and absorbency with a leather-like surface grain. 